The art of handling and packaging articles such as stacks of toweling has not kept pace insofar as all of the major components of a processing line are concerned. For example, a typical line would start with an unwind stand which is capable of operating at speeds of 3,000 to 4,000 feet per minute. Next the unwound web encounters an embosser. The embosser, even more so than the unwind is an expensive piece of equipment and can be operated without difficulty up to speeds in excess of 2,000 feet per minute. Next, the web may be slit into narrower webs where no speed limitation applies. The webs are then superposed (see, for example, co-owned, co-pending Bradley application Ser. No. 77,298 filed Sept. 20, 1979) to move at right angles and pass through a rotary cutter, again operating without any speed limitation. However, the stacks of web material thus provided are then delivered to cartoning equipment and the current state of the art in delivery systems experiences a speed limitation in the range of 500 to 750 feet per minute. Thus, there is a considerable amount of expensive equipment that is severely under-utilized.
As a consequence of this, many manufacturers of flimsy web material--for example, impregnated non-woven materials--have foregone the advantages of rectangular stacks and instead have rewound the web material into cylindrical rolls. Such a roll is inefficient from the standpoint of packaging because most packaging is in rectangular cartons so there is considerable waste space. However, this is currently justified by the fact that rewinding equipment can operate at speeds well in excess of 2,000 feet per minute so the under-utilization referred to above is not experienced--but at the expense of putting out a less efficient product. Thus, the art was faced with undesirable alternatives which have been resolved by the instant invention.
The invention solves this dilemma by (1) operating the expensive major components, viz., unwind stand, embosser, etc. at near their normal speed in a first linear path and thereafter delivering the rectangular stacks of web material in a second linear path at a much lower speed consistent with the limitations of current delivery and packaging equipment. This is achieved by providing a unique arrangement of machine elements operating in a unique sequence of steps.
According to the preferred form of the invention, this is advantageously provided through developing stacks of superposed, rectangular sheets of web material at a predetermined speed and thereafter advancing the stacks along a first linear path at speeds which are at least equal to the predetermined speed and with the long dimension of each rectangular web in a stack being arranged parallel with the first linear path. Thereafter the stacks are sequentially removed from the first path and transferred sequentially into a second linear path which is angularly related to the first linear path and thereby increasing the space between stacks in the second linear path. Finally, the stacks are sequentially retarded in the second linear path to reduce the spacing between the stacks and are then advanced in the second linear path at a speed less than the predetermined speed. This results in the advantageous handling of stacks for packaging and other equipment subject to a speed limitation while being processed in upstream equipment not subjected to the same speed limitation.
Among the advantages accruing from the invention is the significant one of being able to utilize "upstream" equipment to its potential while producing stacks at a rate compatible with the speed limited delivery and cartoning system. Although the concept of transferring rectangular stacks of web material to an angularly related second path while maintaining the orientation the same as it was in the first path (see, for example, co-owned Spencer U.S. Pat. No. 4,283,953) is known, there was no appreciation of the advantages of retarding the stacks in the second path to handle the same compatibly with existing delivery and packaging equipment. More particularly, the greater gap developed by transferring the rectangular stacks from a first path to a second, angularly related path without changing the orientation was not appreciated or utilized heretofore. More especially, the original orientation of the stacks which is perpetuated in the second path is particularly advantageous because there is provided a broad side of the stack for engagement with the retarding means--this is particularly effective in avoiding interleaving, distortion of the pack, wrinkling, etc., as compared with attempting to retard a stack by abutting the narrower end. Thus, the step of retardation, heretofore unappreciated, not only achieves the advantageous compatible utilization of all of the major components of the line but does it in a way preserving of the original character of the stacks developed in the line.
Other objects and advantages may be seen in the details of the ensuing specification.